Pedal key assembly of an electronic musical instrument



United States Patent [72] inventor ShujiMuraki [50] FieldoiSearch............ 84/366. 426, 444, 433, 436, 353

Hamamatsu-shi, Japan.

6 2 4 4 8 S W E mm C e d mT n m nT .k CD R W0 N5 U9 H 2 4 4 l w 6 U 2 a h .5 a ,K m h s u b a K o .n 9 i k %na 1. a 3 A mm. SWPP l i sAnuN 0 e N wm .L no: d i wmaw AFPA UUMM UUHW Hamamatsu-shi, Shizuoka-ken, Japan a corporation of Japan 3,295,402 l/l967 Primary Examiner-Stephen J. Tomsky Assistant Examiner-John F. Gonzales Attorney-George B. Oujevolk [54] PEDAL KEY ASSEMBLY OF AN ELECTRONIC iMUSlCAL'lNSTRUMENT 6 Claims, 7 Drawing Figs.

ABSTRACT: A plurality of parallel arranged pedal key membersare individually swingable on a vertical plane and e corresponding suspension members downwardly extending from the bottom frame of a h t y y b m w w n m 0 m p P w u t s S w .m 8 l .m w t. .S w u H m 4 2 0 4 M N Mb mm 2 G G I. 8 L C L n I s i Patented Sept. 8, 1 10 Sheet 1 of2 I g IAXWTINVENTOR Patented Sept.' 8, 1970 Sheet 7 2 of 2 INVENTOR.

. PEDAL KEY ASSEMBLY OF AN ELECTRONIC MUSICAL INSTRUMENT BACKGROUND OFTHE INVENTION This invention relates to a pedal key assembly of an electronic musical instrument and more particularly to an improvement of suspension'mechanisms for supporting pedal key members.

The prior art suspension mechanisms are mainly disposed in -the musical instrument body and fabricated in such a manner that only the supporting bar of each of said suspension mechanisms extends out from the bottom of said instrument body and is connected to 'the corresponding pedal key member.

Since the main part of the suspension mechanism is located in the instrument body, it is very difficult to adjust the urging force for lifting the key member to the upper limit of its movement while pushing down the corresponding key member, to assemble said suspension mechanism with the key member in such a manner that all the key members are arranged on a common level, and to inspect and, if necessary, repair the assemblies of the key members and suspension mechanisms.

SUMMARY OF THE INVENTION An object of this invention is toprovide a pedal key assembly improved to eliminate the above-mentioned defects.

The pedal key assembly of this invention wherein there are provided a plurality of parallel arranged key members under the bottom frame of an instrument body, each having a suspension member and a pivotally fitting member at which the key member is swingable on a vertical plane, is characterized in that said suspension member involves a supporting bar downwardly extending from i the bottom frame and penetrating the key member, a stop member located at the lower portion of said supporting bar so as to define the limit of the downward movement of said key member, and a compression spring member interposed between the key member and the stop member so as upwardly to urge the key'member.

In this case, a space in the instrument body which, according to the prior art, has been occupied by the suspension mechanisms can be fully utilized by disposing therein switch elements corresponding to the pedal key members.

BRIEF EXPLANATION OF THE DRAWINGS FIG. I is a vertical cross sectional view of a pedal key assembly embodying this invention; FIG. 2 is a cross sectional view of said pedal key assembly 7 taken along a line IlII of FIG. 1;

FIG. 3 is a vertical cross sectional view of a pedal key assembly according to another embodiment of the invention;

FIG. 4 is a plan view of said pedal key assembly of FIG. 3 shown from the underside;

FIG. 5 is a fragmental perspective view of. said pedal key assembly of FIG. 3; FIG. 6 is an exploded perspective view of a pivotally fitting member involved in said pedal keyassembly of the abovementioned embodiments; and

FIG. 7 is anexploded perspective view of a pivotally fitting member modified from that of FIG. 6.

- DETAILED DESCRIPTION OF THE INVENTION An-embodiment of the pedal key assembly of this invention is indicated in FIGS. 1 and 2. Said pedalkey assembly isprovided with a plurality of pedal key members] parallel arranged under the bottom frame 2 of an electronic musical instrument body. Each of said key members I consists of an inverted channel-shaped member or rigid plastic material such as rigid synthetic resin, and has a circular aperture 3 formed on the upper-wall la thereof at the approximately middle portion of-the length of the key member, and an aperture 4 formed on the same wall la at the rear end portion thereof.

Said pedal key assembly further involves a suspension 'member'5 and a pivotally fitting member 6 which correspond to each of the pedal key members I. Said suspension member 5 consists of a supporting bar 5a, a stop member 5b, and a 'the key member l in a manner loosely to pass through said aperture 3. The lower terminal end of said supporting bar 5a is positioned in' the channel of said key member 1. To the lower terminal end of said supporting bar 5a is attached said stop member 5b. In this arrangement, said stop member 5b preferably consists of a hexagonal head integrally formed with the lower end of said supporting bar 5a. Said supporting bar 5a has a screw 7 threaded on the upper peripherythereof. The upper portion of said supporting bar 5a passes through a bore 20 formed in the bottom frame 2 so that said screw is securely set in place by a hexagonal nut 8 carried or welded on the bottom frame 2. A hollow cylindrical member 9 made of synthetic resin is interposed between the frame 2 and stop member 5b, and loosely passes through the circular aperture 3. Said member 9 has a hollow portion 9a through which the supporting bar passes to be covered with saidmember 9. Said member 9 further has a disk 9b integrally formed therewith and superposed on the upper peripheral portion of said stop member 5b by the medium of washer 10.

The above-mentioned compression spring member 50 is preferably formed into a coil in a manner loosely to surround the cylindrical member 9, and interposed between the disk 9b and the portion of the key member I defined around the circular aperture 3.

The suspension member 5 additionally involves an annular member 11 superposed on the peripheral portion of the disk 91?. In order to limit the movement of the key member by the stop member "5b when said key member is downwardly pushed, said key member is provided with an annular seat lb vformed under the aperture 3 in a manner to face said annular member 11 disposed on the stop member 5b in a vertical direction. Said annular member 11 is preferably made of a shock absorbing material such as felt or rubber so as silently to contact the seat lb even when the key member I is roughly operated.

'-For the same purpose of eliminating the noises to be caused, between the key member 1 and bottom frame 2, there is attached by adhesives to either one thereof a shock absorbing member 12 made of foamed synthetic resin or rubber.

The pivotally fitting member 6 indicated in this embodiment consists of a body 6a of elastic material such as rubber having a disk 6b integrally formed with the lower end thereof and an annular groove for engagement with the aperture 4 defined between the disk 6b and the lower surface of the body 6a, and a bar member 6:1 for supporting said body downwardly extending from the bottom frame 2. Said bar member preferably consists of a bolt having a hexagonal head 13 formed at the top thereof, and a nut 14 screwed by a threaded portion formed. at the lower portion thereof. Said bar member 6d downwardly extends through a bore 15 drilled in the bottom frame 2 with its head 13 carried on the bottom frame 2. Said body 6a is interposed between the bottom frame 2 and the rear end portion of the key member 1 by engaging the groove 60 with theaperture 4. In this case, the space between the bottom frame 2 and the rear end portion of the key member 1 is adjusted by advancing or retreating the nut 14 engaged with the screwed portion of said bar member 6d in a manner elastically to deform the body 60, whereby the adjacent key members-l are aligned on a common horizontal level. Mounted on the key member! is an operating member 16 which is vertically moved with the movement of said key member 1. A keying switch mechanism 17 corresponding to said operating member is mounted on the bottom frame 2. Said operating member 16 penetrates the bottom frame 2 and has its top facing the element of said switch mechanism to be switched.

In operation, when the key member is pushed down, it is brought to the lower limit of its movement against the urging force of the compression spring member So so that the key member is swung around the axis defined by the pivotally fitting member 6 due to the deformation of the body 6a caused by the movement of said key member. In this case, any occurrence of frictional or shock noises can be avoided between the key member and the suspension member or pivotally fitting member, because the key member contacts only the elastic member 11 or the elastic body 6a.

When the depressing force of the foot is removed from the key member 1 said key member 1 returns to the upper limit of its movement defined by the cushion piece 12 due to the urging force of the compression spring member.

In this embodiment, since the suspension mechanism is located at the outside of the instrument body, it is very easy to adjust the urging force for lifting the key member to the upper limit'of its movement while pushing down the corresponding key member, to assemble said suspension mechanism with the key member in such a manner that all the key members are arranged on a common level, and to inspect and, if necessary, repair the assemblies of the key members and suspension members. The arrangement of the key members on a common level is ensured by adjustment of the pivotally fitting members as described above. Furthermore, a space in the instrument body which, according to the prior art, has been occupied by the suspension mechanisms is emptied so that it can be fully utilized by disposing therein switch elements corresponding to the pedal key members and relative electrical component.

FIGS. 3 to 5 indicate another embodiment of this invention. In this embodiment, a suspension member 105 particularly consists of a supporting bar 1050, a stop member 105b, a compression spring member 105a and a hexagonal nut 105d. The upper portion of said supporting bar 105a passes through a bore 102a formed on a bottom frame 102 and a head 108 integrally formed with said upper portion is welded on the bottom frame 102. The stop member 105b consists of a cupshaped portion 120 with its sides cut off and opposite wings 121 integrally formed with said cup-shaped portion in a manner to extend therefrom in the lengthwise direction of a key member 101. Said stop member 1051: further involves two contact elements 122a and 1221) made of shock absorbing material such as foamed synthetic resin or rubber and at least covering said wings 121 respectively. Said contact elements 122a and l22b are annularly formed and surround the wings 121 respectively. Said cup-shaped portion 120 is carried on the nut 105d adjustably screwed into the threaded portion of the supporting bar 105a. The compression spring member 105C is formed in the same manner as described in the first embodiment and interposed between the upper wall 101a of the key member 101 and the cup-shaped portion 120 of the stop member.

The remaining parts except those described above are shown in the corresponding figures by the reference numerals having the same digits in the first and second places as those used in the first embodiment, and are omitted from description for avoiding the complicated explanation.

The pedal key assembly of this second embodiment is operated with substantially the same technical effect as described in the first embodiment. In addition, since the parts of contact elements 122a and 122b are permitted to face the inner side walls of the key member 101, the key member 101 when operated is prevented from being displaced in its transverse direction by contacting the stop member through the medium of contact elements, and is also kept free from frictional or shock noises due to the elastic quality of said contact elements.

FIGS. 6 and 7 indicate two modifications of a pivotally fitting member from the first embodiment. The pivotally fitting member 206 shown in FIG. 6 involves a body 206a, a disk 206b, an annular groove 206a and a bar member 206a of .the same type as in the case of the first embodiment. Furthermore, said pivotally fitting member 206 encloses wings 206e extending from the sides of the body 2060 in a transverse direction of the key member and whose lower surfaces are aligned with a plane involving the lower surface of the body,

so that said wings contact the upper surface of the key member. Said wings 206e act to prevent the key member from being rolled around its lengthwise axis.

Each of said wings 206e preferably includes a convex portion or protrusion 200a integrally formed therewith on the under surface, and said key member includes a concave or cut portion 20% formed therewith to fit in with said convex portion or protrusion.

The pivotally fitting member 306 shown in FIG. 7 is not provided with a convex portion or protrusion like that 200a of FIG. 6, but a projection 300a together with separate parts like those indicated in FIG. 6. Said separate parts are shown in FIG. 7 by the reference numerals having the same digits in the first place and characters suffixed thereto as used in the embodiment of FIG. 6. Said projection 300a is disposed in the groove 306C in a manner to bridge the body 306a and disk 306b. In this case, a key member 301 has a cut-off portion 301d formed on the edge of an aperture 304 in a manner to communicate with said aperture, thereby to fit in with said pfoje ction 3000.

The convex and concave portions in FIG. 6 or projection 300a and cut-off portion 301d are used to prevent the wings 2062 or 306e from being rotated around the axis of the bar member 206d or 306d.

Iclaim:

l. A pedal key assembly of an electronic musical instrument comprising a plurality of parallel arranged key members under the bottom frame of an instrument body, each having a suspension member and a pivotally fitting member at which the key member is swingable on a vertical plane, characterized in that said suspension member involves a supporting bar downwardly extending from the bottom frame and penetrating the key member, a stop member located at the lower portion of said supporting bar so as to define the limit of the downward movement of said key member, and a compression spring member interposed between the key member and the stop member so as upwardly to urge the key member.

2. A pedal key assembly claimed in claim 1 in which said key member comprises a channel-shaped member, and said stop member is disposed in said key member and involves contact elements made of shock absorbing material and a least covering the parts of said stop member facing the upper wall of said key member.

3. A pedal key assembly claimed in claim 1 in which said key member involves a vertical aperture formed at the rear end thereof, and said pivotally fitting member comprises a body of elastic material having a disk integrally formed with the lower end thereof and an annular groove for engagement with said aperture defined between the disk and the lower surface Of the body, and a bar member for supporting said body extending from the bottom frame of the instrument body downwards.

4. A pedal key assembly claimed in-claim 3 in which said body of the pivotally fitting member includes wings extending from the sides thereof in a transverse direction of the key member and whose lower surfaces are aligned with a plane involving the lower surface of the body, thereby to cause said wings to contact the upper surface of said key member, and said bar member penetrates said body at its center.

5. A pedal key assembly claimed in claim 4 in which each of said wings includes a convex portion integrally formed therewith on the under surface, and said key member includes aconcave portion formed therewith to fit in with said convex portion.

6. A pedal key assembly claimed in claim 4 in which a projection is disposed in the annular groove of the pivotally fitting member and a cut-off portion is formed on the edge of the aperture at the rear end of the key member to fit in with said projection. 

